package com.cmy.StringBTest;

public class StringBtest {

    public static void main(String[] args) {
        StringBuilder sb = new StringBuilder(10);
        sb.append("hello");
        sb.append(" world");
        System.out.println(sb);
        sb.insert(11,"!!");
        System.out.println(sb);
        sb.delete(11,12);//包前不包后
        System.out.println(sb);

    }


}

    